Asset Management with Remote I/O

As part of the continuous plant optimizing process, remote I/O solutions are gradually replacing conventional wiring solutions at Sasol’s Bruns­büttel plant. These solutions reduce not only wiring and documentation expenditure, but also increase plant capacity and create the foundation for more efficient plant operation using asset management and FDT/DTM.

230 V power supply is sufficient for excom. The expensive 24V cabling is no longer needed

Process optimization

The Sasol plant Brunsbüttel produces fatty alcohols and high-purity alumina. Until recently, Contronic P, an outdated ABB process control system, was used for alumina production. The Sasol specialists successfully replaced it as part of their continual process optimization and were able to migrate to Melody/800xA. Due to switching over to a modern process control system, additional equipment such as controllers, detectors, etc., that were previously located in the switchboard panel of the control room, also had to be converted. Even older field devices and measurement equipment had to be replaced. Sasol connected the new devices using Turck’s excom remote I/O solution. During this project alone, Turck retrofitted a total of ten control cabinets.

24 V line redundant

The specialists at Sasol’s Brunsbüttel plant have been impressed by the efficiency that Turck's modular remote I/O solution provides since the first excom stations were installed in 2005. In the meantime, remote I/Os from Turck are working on almost every process control system at the Brunsbüttel plant to the full satisfaction of its operators.

“During our search for a remote I/O solution that met our requirements, excom was able to score points right from the first presentation with an unbeatable feature: We can operate this system in explosion-hazardous locations using 230 volts,” says Jörg Brouwer, manager of the Process Control Technology department, of the decision at that time in favor of the Turck system.

Conventional remote I/Os require 24 volts. If this voltage is brought into the field over distances of 300 or 400 meters, it requires huge cable cross-sections in order to compensate for the increasing voltage drop with increasing cable length and, in the end, to be able to provide the necessary output. With the use of 230 volts directly on site, these problems are eliminated, conventional cable with normal cross-sections are completely sufficient for this purpose.

30 stations in use

Overall, Sasol has about 30 excom stations in use at the Brunsbüttel plant alone. The remote I/O system for explosion-hazardous locations offers bus-capable, decentralized input/output modules for connecting binary and analog, inherently safe field devices. The system’s protection degree permits use in zones 1 and 2. The field current circuits are permitted for use up to and including zone 0.

Because many users of remote I/O systems benefit from the installation of a fieldbus structure, yet don’t want to sacrifice availability, excom allows a completely redundant set-up. The power supply can be installed in 24 VDC or 230 VAC, with or without a redundancy option. All modules – including the power supply units – can be replaced in zone 1 during operation. In addition to the increased availability, hot swapping and explosion-hazardous location protection, the system permits continuous HART parameterizing of field devices via the bus.